This invention relates to surgical instruments, and in particular to arthroscopic surgical instruments.
Surgical instruments such as for arthroscopy typically include a straight, stationary member that distally supports a surgical tool at a fixed rotational position with respect to the axis of the member. Tissue or bone is exposed to the surgical tool through an opening in the distal end of the stationary member. An actuating member is either rotated or reciprocated to operate the surgical tool and cause it to grasp or sever body material (such as tissue or bone). The actuating member is driven either manually by the user or by a motor. The user (e.g., a surgeon) changes the rotational orientation of the surgical tool by manually rotating the instrument. In some instruments in which the tool cuts tissue, severed body material and irrigation fluid are withdrawn from the surgical site through a transport passage in the actuating member (or through another device) in response to applied suction.
The surgical tool may include a tissue cutting or bone abrading implement, or an implement such as a forceps or grasper for gripping body material. In so-called "punch" arthroscopic instruments, the surgical tool includes a hinged jaw and a stationary jaw mounted on the stationary member near its distal end. The actuating member pivots the hinged jaw, thereby closing and opening the jaws to cut tissue. Examples of these surgical instruments are described in U.S. Pat. Nos. 4,522,206, 4,662,371, both of which are assigned to the present assignee and incorporated herein by reference. In arthroscopic scissor instruments, either or both cutting jaws are hinged. A grasper typically includes jaws that lack cutting edges so as to grasp, rather than cut, body material when the jaws are closed.
Other types of surgical tools include a rotating cutting blade (examples of which are described in U.S. Pat. Nos. 4,203,444, 4,274,414, 4,834,729) or a boneabrading burr (an example of which is described in U.S. Pat. No. 4,842,578). All of these patents are assigned to the present assignee and incorporated herein by reference.
In some arthroscopic instruments the actuating member rotates within the stationary member. The outer, stationary member is sometimes curved to facilitate positioning a cutting implement against tissue to be cut without requiring that the instrument be removed from the body and reinserted through an additional puncture. In one such instrument, the portion of the actuating member disposed within the curve includes a separate flexible section made from a series of coaxial, oppositely-wound spiral layers that enables the actuating member to accept the curvature imposed by the stationary member while transmitting rotational force (i.e., torsion) applied by a driving motor to the blade.